Paul,
I got mine from a guy who built the wing upsidedown. That was why I asked. It can be done. Wasn't trying to be a smart-alec or anything. Hope you didn't take it that way.
But I think Rick maybe right. The wing saddle area was pretty rough on mine. Like someone had to grind out the area to get the wing incidence correct. There is also a good setup sheet in the Futaba 8U manual. It is probably the same one Rick is refering to.

Basically if it pulls to the canopy on a verticle downline you need to sand the trailing edge of the wing saddles. If it pulls to the wheels, add a shim, but make it cover the full length of the root so that you don't stress the saddle in one spot.

Rick,
The OS runs very well with the pump. I used large line with medium line for clamps. the perry pump comes with small nipples. So the medium fuel tube clamps tightened up the seal. I also used the large style craptrap. The carb settings are very close to what you would have with a stock muffler pressure setting. Use some thin double side tape, or a dab of shoe-goo, on the pump if you use the stock clamp, or it will vibrate out.

I didn't make any adjustments on the pump. Of course there is no muffler pressure needed with a pump, so the fuel stays clean.

Unless you cut out the floor of the cockpit, the tank won't quite go back to CG, but far enough. I'm running a 20 oz. tank and am getting 12 minutes plus a bunch, flight time. Very rarely does it fly above 1/2 stick. Mucho Grande power! I used a Slimline Pitts muffler. If I could do it over I'd use the Bisson Pitts style w/70 degree pipes. That way the cowl could go on with no extra holes.
Since the 160 broke in I haven't touched the mixture screws. I could bolt the cowl on and forget it!

Happy Flying!

Scott H.